Closure and contact for mercury switches



March 28,-1950 IE. w. RICKMEYER CLosURE AND CONTACT FCR MERCURY SWITCHESv T 2 Sheets-Sheet l Filed Deo; 15, T945 WMM/'l Marcl 2S, 1950 E. w.RlcKMl-:YER

cLosURE AND CONTACT Foa MERCURY SWITCHES 2 Sheets-Sheet 2 Filed Deo. l5,l:L9-45 .8 7 .Z fofo Patented Mar. 28, 1950 CLGSURE AND1 CONTACT'EORAMERCURY SWITCHES" Ernsti Walter Rickmeyer,l Berkeley,- Ill,assignon to leersernlilectrio Gompany, Bellwood, Ill., a.cernorationofflilinois Kppliczttionecember. 13, 19.45.Serial` No.63.4;777"

provided With restrictedfopeni'ngs therein through'- Whicha conductingfluid! (mercury) maypass'.

2t Gla-ims;I (Cl. 200e-152').

j A: quantity' of mercury i'scontainecl` in one of v the chambers andunder' certain conditions is adaptedv to'flowinto the second chamberthrough therestrictedipassagesin thepar-tition. An elec trical`- contactmember projectsr into the shell through the open end thereof; andmeans"lare provided for hermetically sealingthis openiend oftheshell.Tliemercury bridges a gap between this first' contact member and asecond'- contact so as toclose an electrical' circuit throughv theswitch:` .Y The invention is concerned With-thefrst con tact memberf andthe meansl for ner-meticaily sealing'tfieendof the'vswit'ch shellthroughwhich this contact' projects.

K It'is anfobjectofthe invention to=provide-an effective arrangexnentlfor sealing the endi ci? a rmercuryA switch shell of'this--typef-whileati-the 'same time providing a terminal' connection to thecontaot'memberwith a Very low eiectrical're` sistance'.L notherwords; theinventionlhas the diialf-pur-pose of? effectively sealing the. open. endof? theswitcli shell While `at thesame timeA praviding a low:resistanceA path tot the' mercury through this end ofthe shell. Thisisaccom:- plislfied very` eifectivelyv in a simple'and inexpene sivemanner; and by means' that'k are readily. adaptable to mass production;methods.

` v"'Iflleiforegoingconstitute some"l of the principal objectsl offtideY present'. invention, and" others' will becomeapparent fromareading ofthe following descrilzxtionV and' from the drawings,. inawhich.

` Fig. 1 is a'vertical sectionaLviewtakenithrough acompl'etely:assembled z mercury: switch that eineu bodies one form; of; the;-present: invention;-

2t; is la: top, plan.y View of the: switch; shown im Figi. 12T Eig: 3:isi a, fragmentary verticali sectional: View correspcndingtoilig; 1ibutshowingfa". diierent r embodiment of the invention;

' Fig. vhis a side elevational view. of'tiiefelectrical contact elementshown inlFig. 3';

1 Fig.' 5 isa tcp plan"- viewfoffthef.elementshown iInFi'g.'Y 4.7.

2 6 iisf a vertical sectional" View takenthrougii'aucontactimemberrillustratng a slightly different form of? Contactelement;

Fig: 'Fis-afbottom plan View of the device shown Fig. isv av fragmentaryVertical sectionall View corresponding to-A Fi'gz; but showing stillanothen embodiment: ofvtheV inventiom: and

Fig. 9'? isaf. view. corresponding to Fig. 8, but showing' adiifrcntiembodiment ofstheinvention:

For. purposesr of' illustrationy specific' embodi mentsofftl'ielinvention havezbeen selected; it be-y ing, recognizedi that?manyv different modifications Will occur to the man skilled in the art.Itisv in.- t'endedl that many of these` modications Vmay be made withoutdeparting from the scope ofthe invention.`

Referring tothe drawings', and particularly to Fig. 1`, the'inventionis' shownnas applied to a men cury-switch, generally indicated at l5',andcomprisingv'a sWit-clrishell` lfthat` isl open at one end and isprovided with' v an, annular.' shoulder IlA in;- termediate theA ends'of the'shell1 for supporting a cupellikef` time:L delay7 eleizfient i8;As shown,

`this cup:` t8 comprises sintered` metal: particles totheuppenendtliereoffthatis supported on the. i

topedgeofthelcup L8.v Acopper ring 24, provided WitlfizaLangexZ,isadapted to pass throughthe open sid'ezofthe; cup:` I with.. the;flange1n251resting onY the topzedgeiof thehun. Anbei. washer: 26 is`disposed;v onu the-flange 25, and: the shoulder; Z3 off contactAmember".r 2l? rests" ony this berf- Washer 25. secondfberrwasher 2lsurrounds the 1 up per: end". of? the.` contactmemberf 2|l and restsontop` offtheishouldei 235; Theifshell It. is crimped over: at; 2&1 onta;thelastt4 mentioned: ber washer 255'; and isfpressed;rmlyagainst thisWasher" so as; to. I eifectix'zely: s'eali thecontaci'f.l member 2-.11into tl'ieopern endotheishell IE.

This contactsmemberr 2:! is: maud-,ofa material that: has'theapropertyfof.: readily conducting, elec:- tricalicurrent. Abosselikexportion: 29,` indicated inbrokenslirres; is; initiallyprovid'ed at the,yupper end: cfr the? coc'rtact members 2| f, .and ,a copper: ring 30 isadapted to Iit circumferentially anclfsnugly about3tliis1boss'-likeprojection. 29. This boss-like projection 29 is'tiienA riveted'V over`asN show-1rV at .Si tovforrn am attacking? means to ir-mly secure thecopper ring 30 to the contact member 2l, and to insure good electricalconductivity between this copper ring 36 and the contact member. Thecopper ring 30 is provided with a terminal extension portion 32 to-which a lead wire may be attached. A second copper ring 33 may bemounted concentrically about the lower portion of the switch shell I6,as shown, and a second lead wire may be secured to this latter ring.

A body of mercury 34 is shown disposed in chamber I9 so that anelectrical circuit from the electrical conductor 32 to the copper ring33 is completed through the conducting member 2I, mercury I9, time delaycup I8, and iinally through the wall of the shell I6.

If the switch shell is spun about an axis that is disposed above theshell I6 so that under the influence of centrifugal force the mercury 34is forced against the bottom wall of the cup I8, the mercury will passthrough the restricted openings between the sintered metal particles andflow into the lower chamber ZIJ. A certain time delay is required topass this mercury through the bottom wall of the cup into the lowerchamber 20 due to the fact that air in the chamber 26 must be displaced,and this air must necessarily pass in a reverse direction through therestricted interstices between the metal particles into cham* ber I9. Assoon as the mercury has passed into chamber 26 in a sufiicient amount tolower the mercury level in chamber I9 to a position below the lowermostcontact portion 22 of contact member 2I, the electrical circuit throughthe switch has been broken.

The arrangement shown in Fig. l insures an effective seal of the openend of the switch shell I6. It is important that air be initiallyevacuated from the shell I6 and at all times be prevented from leakinginto chamber I9 in order to prevent the occurrence of oxidation tothereby insure at all times good electrical contact between the mercuryand the contact member 2 I.

Since the entire contact member 2I, as shown in Fig. l, is made ofmetal, it is essential that all parts of this contact member bevelectrically insulated from the shell I6 and the time delay cup I8. Asshown, the ber washers 26 and 21 serve to insulate the contact memberand to space the shoulder 23 thereof from the walls of the shell I 6.

It may be desirable to provide a contact member that is mostlynon-metallic and that in itself is non-conductive. In Fig. 3, such anarrangement is shown, where a contact member, generally shown at 35,comprises a plug or end closure portion 36 of Bakelite, or likenon-conducting material, that is molded about a cup-like or cupshapedelectrical conducting element 31. This plug 36 is provided with anannular shoulder 38 that corresponds with the shoulder 23, previouslydescribed. The manner of sealing this plug 36 in the open end of the cupshell is in accordance with that previously described in connection withthe contact member 2I of the rst embodiment of the invention. Thecup-like or cup-shaped contact element 31 per se is shown in Figs. 4 and5, and comprises an upwardly opening cup-like or cupshaped portion 39having an upstanding lead or electrical conducting member 46 forIsecuring thereto an electrical conductor. The-entire contact element31may be made of copper or some other such material having highelectrical conductivity.

As shown in Fig. 6, a similar arrangement to that shown in Fig. 3 may beutilized, but in this instance a conducting element 4I,may be em- 4ployed where the lower portion. indicated at 42, constitutes a ringrather than a cup-like portion 39, as shown in Fig. 4.

In Fig. 8, a somewhat different form of the invention is shown. In thisinstance, a plug 43 is employed together with a cup-like element 44 thatcompletely encloses a downwardly project. ing boss 45 forming part ofthe plug 43. In this instance, the lower portion of the conductingelement 44 is in the form of a cup 46 that is relatively deep and isflared as at 41. This ared portion 41 is contained within the body ofthe plug 43, as was the case with the plug 35 shown in Fig. 3. This plug43, together with its downwardly extending boss portion 45, may be madeof Bakelite, and, again, is provided with an outwardly extending annularflange or shoulder portion 48. This shoulder portion 48 is adapted to besupported on the time delay cup I 8 in the mercury switch shell I6. Inthis case, however, a. seal is eiected by an irregularly shaped copperring element 49 that passes between the wall of the shell I6 and theside and lower faces of the annular shoulder 48. This sealing ring 49has a. downwardly extending flange 50 that projects into the time delaycup I8, and also is provided with an upwardly extending flange portion5I that is crimped inwardly upon the top surface of the shoulder 48. Theupper edge 28 of the shell Il, in this instance, is crimped over ontothe ring ange 5I and then this last named ange is curved backwardlyagainst the crimped over portion 28 of the shell. In this manner, theopen end of the shell I6 is effectively sealed. In this embodiment ofthe invention, the walls of the cup 46 are exposed to the interior ofchamber I9, and are subject to be contacted by the mercury in thischamber throughout substantially the entire depth of this cup portion46. Thus, in this form of the invention, a longer contact between themercury and the contact element 44 can be effected than in the case ofthe embodiment shown. for example, in Fig. 3.

Fig. 9 illustrates still another embodiment of the invention. In thisinstance, the contact member, generally shown at 55, comprises a.metallic contact element, generally indicated at 56, that is supportedby an insulating portion 51 of Bakelite or like material. This contactportion 56 is provided with a lower end portion 58 having an upwardlyextending portion 59 of less diameter. The insulating portion may bemolded circumferentially by the upstanding portion 59 of the contactmember, and is provided with an annular shoulder 60 that serves in thesame manner as the previously disclosed shoulders 23, 3l, and 48, forexample. In this embodiment of the invention, the central portion 59 ofthe contact member 56 initially projects above the insulating portion51, as indicated in broken lines at 6I, and a copper ring 62 is mountedover this projecting portion. This ring 62 is firmly held against thetop of the insulating portion 51 by riveting over the upstanding portion6I, as shown at '63. Good electrical conductivity again is providedbetween the ring 62 and the contact portion 56.

As in the case of the embodiment shown in Fig. l, the copper ring 24with its outwardly extending flange 25 is provided at the open end ofthe time delay cup I8, the flange 25 resting on the top edge of the cupI8. A gasket 64 is inserted between the shoulder 60 and the shell I 6and flange 25 of ring 24. This gasket 64 is provided with an upperportion 65 that is bent over onto the top surface of the shoulder GII.

and then the open edge 28 of the shell I6 is crimped over against thisportion 65 of the gasket with sui'cient pressure to eiectively seal theopen end of the shell.

The ring 62 corresponds with ring 30 in the embodiment shown in Fig. 1and serves as one terminal connection to the mercury switch. A secondring 33 is provided, as before, to serve as the second terminalconnection to the switch.

In this form of the invention, an electrical circuit through the switchis completed so long as the mercury is in engagement With the exposedsurfaces of the lower portion 58 of contact element 56.

I claim:

1. A contact member for use in an open shell of the type describedcomprising an open cupshaped contact portion, an upstanding elongatedconductor attached to the side Wall of the cup, a closure portion insaid cup-shaped portion and projecting thereabove, said closure portionncludlng an annular shoulder projecting laterally beyond the outerlimits of the cup-shaped portion, the conductor passing through theclosure portion and connecting the cup-shaped portion with meansadjacent to the top of the closure portion for attaching thereto anelectrical conductor.

2. In a mercury switch, a shell having an open end, an annular shoulderin the shell adjacent to the open end thereof, a Contact memberincluding an end closure portion for the shell, and electricalconducting means projecting through the contact member into the shellinterior, said contact member including an upwardly opening cupshapedmember of electrical conducting material having outside surfaces exposedto the interior 0f the shell, and mercury in the shell for conducting anelectrical current from outside the shell to the cup-shaped portion.

ERNST WALTER RICKMEYER.

REFERENCES CITED The following references are of record in the iile ofthis patent:

UNITED STATES PATENTS Number Name Date 2,251,011 Bear July 29, 19412,265,681 Bear et al. Dec. 9, 1941 2,297,924 Trautman et al. Oct. 6,1942 2,414,836 Rickmeyer Jan. 28, 1947

